1~120內數字是6的倍數有:
6x1, 6x2, 6x3, 6x4, 6x5, 6x6, 6x7, 6x8, 6x9, 6x10,
6x11, 6x12, 6x13, 6x14, 6x15, 6x16, 6x17, 6x18, 6x19, 6x20 共 20個。
其中 6x4, 6x8, 6x12, 6x16, 6x20 都是 8的倍數,所以不是 8的倍數有:
6x1, 6x2, 6x3, 6x5, 6x6, 6x7, 6x9, 6x10, 6x11, 6x13, 6x14, 6x15, 6x17, 6x18, 6x19. 即
6,12,18,30,36,42,54,60,66,78,84,90,102,108,114。